Method and apparatus for eliminating vapor lock in internal combustion engines



1962 w. w. DICK 3,065,702

METHOD AND APPARATUS FOR ELIMINATING VAPOR LOCK IN INTERNAL COMBUSTION ENGINES Filed Oct. 28, 1959 A IR CLEANER ulllllll IIIIII/I'llllllllln 4Q. QQ 2 \ax m gzh 22m ENTOR E ATTORNEY] United States Patent Ofitice 3,%5,72 Patented Nov. 2?, 1962 METHOD AND APPARATKE FDR EHMlNATlNG VAPQR LQCK IN KNTERNAL CQMBUSTHQN ENGINES Wade W. Dick, Shreveport, La., assignor of one=half to Carl L. Morris, Oil City, La. Filed Oct. 28, 195?, Bar. No. 849,346 7 Claims. (Cl. ins-e2) My invention relates broadly to a method and apparatus for eliminating vapor lock in internal combustion engines and more particularly to an insertable disc containing a bypass valve for insertion in conventional diaphragmtype automotive fuel pumps for automatically by-passing any excessive pressure occurring in the fuel pump discharge line to the carburetor, back into the fuel pump suction stream to eliminate vapor lock.

One of the objects of my invention is to provide a construction of anti vapor lock apparatus for automotive fuel pumps which is simple in design, easy to install without special tools, and which does not require any modification to existing fuel pump components.

Another object of my invention is to provide a method and apparatus for eliminating vapor lock in internal combustion engines which by-passes excessive fuel pump discharge pressure back into the fuel pump suction section to eliminate vapor lock in internal combustion engine fuel pumps.

Another object of my invention is to provide a simple construction of anti-vapor lock device in which a simple ball valve construction bleeds excessive pressure from one section of the fuel pump to another section of the fuel pump.

Other and further objects of my invention reside in the by-pass valve construction which enables maintenance thereon without disassembly of the fuel pump as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

FIG. 1 is a schematic View of a typical fuel delivery system of a standard internal combustion engine;

FIG. 2 is a side elevation view partly in cut-away section showing the anti-vapor lock device of my invention installed on a conventional diaphragm-type automotive fuel pump;

FIG. 3 is an enlarged sectional view of a fragmentary portion of FIG. 2 particularly showing the by-pass valve construction;

FIG. 4 is a fragmentary vertical sectional view taken substantially on line i4 of FIG. 3;

FIG. 5 is a perspective view of the anti-vapor lock disc of my invention;

FIG. 6 is a fragmentary cross-sectional view taken substantially on line 6-6 of FIG. 2; and

FIG. 7 is an enlarged fragmentary sectional view similar to FIG. 3 but showing a modified arrangement of bypass valve in the anti-vapor lock device of my invention.

My invention is directed to a by-pass system for insertion on conventional diaphragm-type automotive gasoline fuel pumps which comprises a by-pass valve carrying disc member which becomes an integral part of the conventional fuel pump. By the insertion of the by-pass valve carrying disc of my invention on a fuel pump any over pressure occurring in the discharge line and chamber to the carburetor can be bled back into the suction stream or suction section of the fuel pump, thus equalizing in a relative sense the pressures on the suction and discharge sides of the pumping mechanism and thus preventing the phenomenon known as vapor lock.

The anti-vapor lock device of my invention provides an orifice opening into the discharge chamber of the fuel pump and a pressure actuated ball valve mechanism or one-way opening check valve connecting the orifice through a channel to an aperture, carried by the anti-vapor lock device, which constitutes a channel in the suction stream on the suction side of the fuel pump. The ball valve is normally closed and as excessive pressure occurs in the fuel pump discharge chamber, the normal cause of vapor lock, the ball valve is opened and the excessive pressure is bypassed back into the suction stream or input side of the fuel pump, thus relieving the pressure in such a manner as to eliminate the possibiltiy of vapor lock. The by-pass valve comprises a coil spring holding a ball valve on its seat, and the spring is tensioned so as to permit the ball valve to become unseated at a slightly lower pressure than the fuel pump is designed to deliver.

Referring to the drawings in greater detail I have illustrated in FIG. 1 a typical automotive fuel delivery schematic diagram in which the fuel tank is represented at 1 delivering gasoline by means of fuel pump suction line 2 to the fuel pump shown at 3 operated by lever arm 4 riding on camshaft 5 in the internal combustion engine represented at 6. Fuel pump 3 then delivers gasoline through fuel pump discharge line 7 to the carburetor represented at 8, or a fuel injection system in lieu thereof.

In FIG. 2 I have shown the type of automotive fuel pump on which the anti-vapor lock apparatus of my invention can be installed. The fuel pump shown is a conventional diaphragm type consisting of the upper main casting 9, fuel pump diaphgram it}, lower main casting ill, and the sediment bowl support casting 12 carrying sediment bowl l3 detachably attached thereto by means of bracket 14 and adjustable coupling 15. The upper main casting 9 houses the coupling link between the lever arm 4 and the fuel pump diaphragm 10 which permits the lever 4 to control the operation of the diaphragm 10, which is secured between the upper main casting 9 and the lower main casting 11. The lower main casting 11 carries a circularly formed centrally disposed intake channel 16 leading to the input side of the fuel suction valve mechanism, carried interiorly thereof as indicated at 17, which is controlled by the diaphragm 10. The fuel suction valve mechanism, which contains both suction and discharge valves and which constitutes the main mechanism of the fuel pump, pumps the fuel or gasoline into the chamber 18 from which it is discharged under pressure to the carburetor 8 by way of fuel pump discharge line 7 connected to the lower main casting 11. The centrally disposed intake channel 16 provides a centrally disposed mounting post 19 for receiving bolt 20 which normally secures the sediment bowl support casting 12 directly to the lower main casting 11.

The anti-vapor lock apparatus of my invention is disposed between the lower main casting Ill, or the portion carrying the fuel discharge chamber and fuel suction section, and the sediment bowl support casting 12, or the portion carrying the full input port, andis comprised of a circular disc member 21 or a plate member, having a series of apertures 22 therethrough, disposed in close symmetrical arrangement about a centrally disposed aperture 23 in such a manner as to align with the apertures 22', 22", and the central apertures 23 and 23" of the gaskets 24 and 25 respectively. The gasket 24 with its arrangement of apertures 22 and 23' is a standard gasket which is part of the original fuel pump 3 and in the original assembly the sediment bowl support casting 12 is sealed to the lower main casting 11 by the gasket 24. When the anti-vapor lock disc or plate 21 is interposed between these two castings, gasket 24 seals disc 21 to lower main casting 11 and gasket 25, which is a duplicate of gasket 24, seals disc 21 to sediment bowl support casting 12, the entire assembly being secured together by bolt 26 as shown in FIGS. 2 and 3. The holes 22, 22' and 22" of disc 21, and gaskets 24 and 25 respectively transmit the suction from intake channel 16 of the lower a main casting 11 down through the outer intake channel 26, filter 27, sediment bowl 13, inner intake channel 28 (which contains the bolt 28) and fuel input port or suction opening to the fuel tank 29, of the sediment bowl support casting 12, and through fuel suction line 2 to the fuel tank 3..

The disc 21 contains a boss or boss member 30 on the upper surface thereof having a downwardly extending orifice 31 therein disposed substantially parallel with apertures 22 and 23 and intersecting by-pass channel 32 at substantially right angles. By-pass channel 32 is dis posed to intersect one of the apertures 22 at right angles and provide an opening on the exterior edge of disc 21 as shown at 33. Spring 34 is disposed in channel 32 so as to traverse the diameter of aperture 22, one end of the spring being slightly recessed in the wall of aperture 22 and the other end of the spring engaging ball 35 so as to bias it into the centrally apertured ball valve seat 36 threaded into by-pass channel 32. The exterior end of by-pass channel 32 as shown at 33 is sealed by the removable plug 37 threaded therein to provide access to the by-pass valve for maintenance without removing the disc 21 from the fuel pump.

The disc 21 is assembled onto the fuel pump in abutment with gasket 24 with orifice 31 opening into the fuel pump discharge chamber 18 and spring 34 holding ball 35 against its seat 36 to prevent any leakage which would affect the suction efficiency of the fuel pump under ordinary conditions. When excessive pressure occurs through the discharge section of the fuel pump, that is, in chamber 18, the excessive pressure is dissipated or relieved by a back flow through orifice 31 from chamber 18, into bypass channel 32, through the orifice in the valve seat 35 which dislodges the ball from the seat and permits the excessive discharge pressure to the carburetor to be bypassed back into one of the apertures 22, thus the excessive pressure finds its way back into the suction section of the fuel pump. By relieving the excessive discharge pressure back into the suction section of the fuel pump the fuel pump suction and discharge valve mechanism is relieved from the possibility of being locked due to excessive pressure on the discharge end thereof. In this manner the possibility of vapor lock is eliminated.

The upper gasket 24 contains a hole shown at 38 which performs two separate functions. First it provides an opening for the orifice boss 30, and second it provides a reference means for perfectly aligning the gasket apertures 22', 23 with the apertures 22, 23 of the disc 21. In like manner the lower gasket 25 is provided with a hole 38 which fits over boss 39 on the lower surface of disc 21 so that the apertures 22", 23 are held in perfect alignment with the apertures 22, 23 of disc 21.

The tension of spring 34 is relatively light in comparison with the pressure that the fuel pump actually delivers to the carburetor and creates in chamber 18. For example, if the fuel pump is designed to deliver fuel at psi. to the carburetor, spring 34 is tensioned to permit ball 35 to be dislodged from its valve seat 56 at a pressure of approximately 3 psi. in chamber 18. Since orifice 31 is very small there naturally is a very slight amount of fuel being by-passed through the by-pass valve during operation of the vehicle, but this small orifice is sufiicient to relieve the excessive pressure in the line to the carburetor from the discharge section of the fuel pump since there is such a small volume involved. This vapor lock by-pass apparatus of my invention also tends to dampen erratic pulsations of the fuel pump, resulting in a more even flow of fuel to the carburetor while at the same time dissipating the high pressure in the discharge line incurred during hot weather operation or during heavy trafiic starting and stopping conditions. Also in high altitude operation my device relieves any possibility of vapor lock due to high vapor pressures holding down the discharge valve of the fuel pump and making it impossible for the pump mechanism to function.

In FIG. 7 I have shown a modified construction of the vapor lock by-pass valve of my invention. FIG. 7 illustrates an enlarged cross-sectional view of a portion of the disc 21 carrying suction aperture 22" and a bypass valve connected therewith by means of channel 40 which is sealed on the exterior end thereof by the threaded plug 41. As in the principal form of my invention a boss 36 is provided on the top surface of disc 21 which provides a downwardly depending orifice 31', but in this modified form of my invention the orifice 31 opens into an eniarged channel 42 disposed in axial alignment with orifice 31' and provides a ball valve seat at the junction of orifice 31 and channel 42 as shown at 43. Ball valve 35 is held against its seat 43 by spring 34 which is axially disposed in channel 42 and secured therein by removabie plug 37' sealing the lower end of channel 42. Channel 4t intersects channel 42 at substantially right angles such that pressure relief flow from the chamber 18 back to the suction side of the fuel pump is directed through the orifice 31', around the ball valve 35' when it is open, into channel 42 and then into aperture 22', which is on the suction side of the fuel pump, by means of channel 40.

I have constructed and exhaustively tested the method and apparatus of my invention for eliminating vapor lock in internal combustion engines and have found it extremely reliable, efiicient and effective. While I have described my invention in certain preferred embodiments I realize that modifications can be made, and I desire that it be understood that no limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In an automotive fuel pump a lower casting carrying a fuel input port and suction channel, an upper casting carrying a fuel discharge chamber and fuel suction section, a disc disposed between said upper casting and said lower casting, said disc having apertures therein connecting said upper casting fuel suction section and said lower casting suction channel, said disc carrying a by-pass valve therein, and said by-pass valve disposed to connect said fuel discharge chamber with one of said apertures under varying.

pressure conditions in said discharge chamber.

2. In an automotive fuel pump as set forth in claim 1,- said by-pass valve being operable at a pressure lower than the pressure the fuel discharge chamber is designed to deliver.

3. In an automotive fuel pump as set forth in claim 1, said by-pass valve comprising a downwardly extending orifice, said downwardly extending orifice opening into a channel disposed normal to one of said apertures, a coil spring traversing one of said apertures and extending into said channel, said coil spring disposed to hold a ball valve against seating means disposed in said channel, and said ball valve movable to an unseated position upon excessive pressure occurring in said discharge chamber.

4. An anti-vapor lock device for automotive fuel pumps as set forth in claim 7 in which said by-pass valve includes a removeable access plug on the exterior circumferential surface of said insertable disc member.

5. An anti-vapor lock device for automotive fuel pumps as set forth in claim 7 in which said by-pass valve constructed and arranged within said insertable disc member comprises a valve mechanism disposed in axial alignment with said orifice and a connecting channel disposed between said valve mechanism and said suction aperture means.

6. An anti-vapor lock device for automotive fuel pumps as set forth in claim 7 in which said by-pass valve constructed and arranged within said insertable disc member includes a compressible spring member disposed in parallel alignment with said suction aperture means.

7. An anti-vapor lock device for automotive fuel pumps comprising an insertable disc member, a fuel pump, said fuel pump including a lower fuel pump portion having a fuel input port and suction channel, and an upper fuel pump portion having a fuel discharge chamber and fuel suction section, said disc member being insertable on said fuel pump intermediate said lower portion having the fuel input port and suction channel, and said upper portion having the fuel discharge chamber and fuel suction section, said disc member having suction aperture means therein connecting said lower portion suction channel and said upper portion fuel suction section, an orifice opening on one surface of said disc member into the fuel discharge chamber of said upper fuel pump portion, a by-pass valve constructed and arranged Within said inserta'ble disc mem- References Qited in the file of this patent UNITED STATES PATENTS 1,989,404 Harman et al Nov. 13, 1934 2,146,398 Laiferty Feb. 7, 1939 2,3 89,159 Lowther Nov. 20, 1945 

